CN106090111B - A kind of adaptive damping hydraulic vibration damper used for vehicle with height adjusting system - Google Patents

Abstract

The invention provides a variable damping automotive hydraulic shock absorber with a height adjustment system, comprising a damping system and a height adjustment system; the damping system includes a piston rod, a piston head, a spring assembly, an inner cylinder, an outer cylinder and variable damping Control valve; the height adjustment system includes air compressor, air compressor control unit, front axle height sensor, rear axle height sensor, pressure sensor, signal control center, cylinder head, air bag and cylinder barrel; the inner barrel is divided into active Rod chamber and rodless chamber; the outer cylinder is separated by the lower end cover of the inner cylinder into the oil storage chamber of the outer cylinder and the oil storage chamber of the floating piston; the two oil ports of the variable damping control valve communicate with the oil storage chamber of the outer cylinder and the rodless chamber respectively The floating piston isolates the oil from the air spring chamber, and the oil circulates back and forth between the rodless chamber and the rod chamber through the variable damping control valve and a series of damping holes, and cooperates with the height adjustment system to compress or pull the shock absorber The corresponding height compensation can be made while stretching, which can obtain good vibration reduction effect and ride comfort.

Description

A variable damping automobile hydraulic shock absorber with height adjustment system

technical field

The invention belongs to the research field of automobile shock absorbers, in particular to a variable damping automobile hydraulic shock absorber with a height adjustment system.

Background technique

The vehicle suspension and vibration damping control system is the link between the car frame and the axle, and it is the carrier of the body mass and the link of vibration attenuation. If the road surface is uneven when the car is running, the vehicle suspension and shock absorber bear and transmit the load in the vertical direction, limiting the vibration frequency and strength of the body and wheels.

Ideally, it is hoped that the reciprocating motion of the piston rod of the shock absorber can limit the up and down floating of the car body to achieve the effect of smooth running of the car body. However, in fact, when the road conditions are relatively bad or the driving style is special, the floating range of the piston rod is limited, and the front of the car There will be a phenomenon of "nodding" or "head up", which will affect the driver's line of sight or the obstacle avoidance of the vehicle body. At this time, it is very important to adjust the level state of the vehicle suspension.

So far, the Chinese patent application number CN105196825A proposes a height control system for automotive mechanical air suspension, which mainly includes an oil storage tank and a height valve. This patent mainly realizes height control through a mechanical linkage. The precision is not high; the Chinese patent application number CN104534007A proposes a height valve built-in spring shock absorber assembly, which mainly includes an air spring and a shock absorber. In this patent, the height valve is built into the air spring to cooperate with the shock absorber control, but Its shock absorber cannot realize variable damping control, and the vibration reduction mode is single.

Contents of the invention

The object of the present invention is to provide a variable damping automotive hydraulic shock absorber with a height adjustment system to solve the above problems, which can realize automatic adjustment of the vehicle body height and variable control of the damping coefficient at the same time.

The technical solution of the present invention is: a variable damping automotive hydraulic shock absorber with a height adjustment system, including a vibration reduction system and a height adjustment system; the vibration reduction system includes a piston rod, a piston head, a spring assembly, an inner cylinder, Outer cylinder and variable damping control valve; the height adjustment system includes an air compressor, an air compressor control unit, a front axle height sensor, a rear axle height sensor, a pressure sensor, a signal control center, a cylinder head, an air bag and a cylinder barrel;

One end of the piston rod is threadedly connected to the piston head and coaxially installed in the inner cylinder, and the piston head and the inner cylinder have an interference fit; the inner cylinder is a cylindrical thin-walled structure, and one end is blocked by the lower end cover of the inner cylinder , the other end is blocked by the upper end cover of the inner cylinder; the other end of the piston rod protrudes through the center hole of the upper end cover of the inner cylinder, and the piston rod is placed on the inner section of the inner cylinder through the piston guide and sealing assembly to achieve a sealed connection ; The spring assembly is located in the inner cylinder and coaxially sleeved on the piston rod, one end of the spring assembly is against the piston head, and the other end is against the piston guide and sealing assembly;

The outer cylinder is sleeved on the outside of the inner cylinder and sealed with the lower end cover of the inner cylinder; since the lower end cover of the inner cylinder is larger in diameter than the inner cylinder, an annular outer cylinder oil storage chamber is formed between the outer cylinder and the inner cylinder;

The cylinder barrel is a U-shaped thin-walled structure, the lower end is sleeved on the outer cylinder, the upper end is fixedly connected to the inner side of the airbag, the outer side of the airbag is fixedly connected to the lower end of the cylinder head, and an air valve joint is provided on the cylinder head;

The cylinder head has an annular groove structure, and a cylinder head limit sleeve is arranged in the annular groove, the piston head buffer assembly is installed in the cylinder head limit sleeve, and the end of the piston rod extending outside the inner cylinder passes through the cylinder head in turn The center hole of the limit sleeve and the piston head buffer assembly is connected with the piston head buffer assembly through threads;

The piston head is provided with a damping hole e and a damping hole d, and the rod chamber and the rodless chamber communicate with the damping hole d through the damping hole e;

The variable damping control valve is connected with the lower end cover section of the outer cylinder close to the inner cylinder through bolts, and the damping hole c on it communicates with the oil storage cavity of the outer cylinder, and the damping hole b communicates with the rodless cavity; There is a damping hole f on the side of the cavity, and the rod cavity communicates with the oil storage cavity of the outer cylinder through the damping hole f;

The air compressor and the air compressor control unit are integrated and installed on the vehicle suspension, the front axle height sensor is installed on the front axle of the vehicle frame, and the rear axle height sensor is installed on the rear axle of the vehicle frame to measure the height of the vehicle frame, and Transmit the altitude signal to the signal control center; the signal input end of the pressure sensor is connected to the air compressor control unit, and the signal output end is connected to the signal control center to measure the pressure of the airbag and transmit the pressure signal to the signal control center; the signal The processing center sends instructions to the air compressor control unit and the variable damping control valve, the air compressor control unit controls the operation of the air compressor, and at the same time the variable damping control valve is adjusted to the required compression damping coefficient.

In the above scheme, a floating piston is also included; the end of the outer cylinder is provided with an outer cylinder plug; the floating piston is installed in the outer cylinder between the lower end cover of the inner cylinder and the outer cylinder plug, and interferes with the outer cylinder Cooperate;

A compensation cavity is formed between the lower end cover of the inner cylinder and the floating piston, and a plurality of damping holes a communicating with the compensation cavity are provided on the lower end cover of the inner cylinder;

There is an air spring between the floating piston and the plug of the outer cylinder.

Further, the plug of the outer cylinder is connected to the outer cylinder through threads.

Further, an inflation valve is provided on the plug of the outer cylinder; the inflation valve is screwed onto the plug of the outer cylinder through threads.

In the above solution, the two sides of the piston head are respectively equipped with a valve plate a and a valve plate b; the valve plate a and the valve plate b are respectively sleeved on the piston rod and fixedly connected by bolts;

The damping hole e is covered by the valve plate a, and the damping hole d is covered by the valve plate b.

In the above solution, an airbag protective cover is also included; the upper end of the airbag protective cover is connected with the cylinder head through a buckle.

In the above solution, the outer side of the cylinder barrel is covered with a rubber protective sleeve.

In the above solution, a rubber buffer sleeve is also included; the rubber buffer sleeve is sleeved on the piston rod and is located outside the inner cylinder. The end is sleeved on the piston rod and is pressed against the lower end of the piston head buffer assembly.

In the above solution, an instrument display is also included; the instrument display is connected with the signal control center and can display the detection data of each electrical part in real time.

In the above solution, the damping hole e and the damping hole d are inclined or L-shaped or Z-shaped.

The beneficial effects of the present invention are: compared with the prior art, the present invention integrates the air bag and the shock absorber, has a compact structure, is easy to install, and can be used in combination with the height adjustment system and the shock absorber to limit the rate of change of the vehicle body level , to obtain good passenger comfort; the height adjustment system in the present invention can automatically sense the vibration amplitude of the frame and the levelness of the vehicle body through the height sensor, and automatically adjust the height of the vehicle body as required, with strong controllability and high sensitivity; The variable damping control valve used in the invention is used in conjunction with the air spring, which combines the dual performances of high hydraulic oil stiffness and good air spring compressibility, and can obtain a good vibration damping effect; the invention sets a detachable valve with an air charging valve at the end of the outer cylinder. The outer cylinder plug is convenient for filling inert gas after product assembly, the processing and manufacturing process steps are more reasonable, and the debugging and maintenance are convenient.

Description of drawings

Fig. 1 is a structural schematic diagram of a variable damping automobile hydraulic shock absorber with a height adjustment system according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of composition and connection of a height adjustment system according to an embodiment of the present invention;

3 is a schematic diagram of oil flow in a compressed state of a hydraulic shock absorber according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of oil flow in a stretched state of a hydraulic shock absorber according to an embodiment of the present invention.

In the figure: 1. Air valve joint; 2. Cylinder head; 3. Airbag protective cover; 4. Airbag; 5. Cylinder barrel; 6. Upper end cover of inner cylinder; 7. Rubber protective sleeve; 8. Inner cylinder; Rod; 10, spring assembly; 11, outer cylinder; 12, valve plate a; 13, damping hole d; 14, valve plate b; 15, damping hole c; 16, variable damping control valve; 17, damping hole b; 18. Lower end cover of inner cylinder; 19. Floating piston; 20. Plug of outer cylinder; 21. Inflatable valve; 22. Air spring; 23. Compensation cavity; 24. Damping hole a; 25. Rodless cavity; 26. Outer cylinder Oil storage chamber; 27. Piston head; 28. Damping hole e; 29. Rod chamber; 30. Damping hole f; 31. Piston guide and sealing assembly; 32. Rubber buffer sleeve; 33. Outer cover guide sleeve; 34. Cylinder head limit sleeve; 35. Piston head buffer assembly; 36. Air compressor; 37. Air compressor control unit; 38. Front axle sensor; 39. Rear axle sensor; 40. Instrument display; 41. Pressure sensor; 42. Signal processing center.

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals represent the same or similar parts. The accompanying drawings are only used to illustrate the present invention, and do not represent the actual structure and true scale of the present invention.

Fig. 1 shows an embodiment of the variable damping automotive hydraulic shock absorber with a height adjustment system of the present invention, the variable damping automotive hydraulic shock absorber with a height adjustment system includes a vibration damping system and a height adjustment system. The damping system includes an inner cylinder 8, a piston rod 9, a spring assembly 10, an outer cylinder 11, a valve plate a12, a valve plate b14, a variable damping control valve 16, an inner cylinder lower end cover 18, a floating piston 19, and an outer cylinder plug Head 20, inflation valve 21, piston head 27, piston guide and sealing assembly 31, etc. The height adjustment system includes air compressor 36, air compressor control unit 37, front axle height sensor 38, rear axle height sensor 39, pressure sensor 41, signal control center 42, cylinder head 2, air bag 4 and cylinder barrel 5, etc.;

The piston head 27 is connected with one end of the piston rod 9 through threads, and is installed coaxially in the inner cylinder 8 as a whole. A seal is arranged on the circumference of the piston head 27 to interfere with the inner cylinder 8 to prevent oil on both sides from Mutual channeling, so that the piston head 27 divides the inner cylinder 8 into two chambers, namely a rod chamber 29 and a rodless chamber 25. The inner cylinder 8 is a cylindrical thin-walled structure, one end of the inner cylinder 8 is fixed and sealed with the lower end cover 18 of the inner cylinder, the other end is fixed and sealed with the upper end cover 6 of the inner cylinder, and the other end of the piston rod 9 passes through the upper end cover of the inner cylinder 6, and the piston rod 9 is placed on the inner section of the inner cylinder 8 through the piston guide and sealing assembly 31 to achieve a sealed connection. The spring assembly 10 is located inside the inner cylinder 8, and coaxially sleeved on the piston rod 9, one end of the spring assembly 10 is against the piston head 27, and the other end is against the piston guide and sealing assembly 31; the rubber buffer sleeve 32 is set on the On the piston rod 9, and located outside the inner cylinder 8, the outside of the rubber buffer sleeve 32 is surrounded by a U-shaped outer cover guide sleeve 33 and limits its circumferential deformation and radial displacement; the outer cylinder 11 is sleeved on the outside of the inner cylinder 8, and The lower end cover 18 of the inner cylinder is fixed and sealed. Since the diameter of the lower end cover 18 of the inner cylinder is larger than that of the inner cylinder 8, an annular outer cylinder oil storage chamber 26 is formed between the outer cylinder 11 and the inner cylinder 8; the floating piston 19 is installed in the outer cylinder 11 Located between the lower end cap 18 of the inner cylinder and the plug 20 of the outer cylinder, a sealing member is provided on the circumference of the floating piston 19 for interference fit with the outer cylinder 11; a compensation chamber 23 is formed between the lower end cap 18 of the inner cylinder and the floating piston 19, The lower end cover 18 of the inner cylinder is provided with a plurality of damping holes a24 communicating with the compensation cavity 23; the end surface of the lower end cover 18 of the inner cylinder is provided with a plurality of damping holes a24 communicating with both ends, and all the damping holes a24 are evenly distributed in the inner cylinder. In the annular surface of the cylinder 8, the oil can only enter the compensation chamber 23 through a series of damping holes a24 on the lower end cover 18 of the inner cylinder; the end of the outer cylinder 11 is provided with a threaded outer cylinder plug 20 for thread-tight connection, The charging valve 21 is screwed on the plug 20 of the outer cylinder; the space between the floating piston 19 and the plug 20 of the outer cylinder is filled with compressed gas through the charging valve 21 to form an air spring 22 .

The cylinder barrel 5 is a U-shaped thin-walled structure, the lower end of the cylinder barrel 5 is sleeved on the outer barrel 11, and is connected with the outer barrel 11 by welding; The lower end is fixedly connected, and the air valve connector 1 is set to be screwed on the cylinder head 2. An airbag protective cover 3 is arranged outside the airbag 4, and the upper end of the airbag protective cover 3 is connected with the cylinder head 2 through a buckle. The outer side of the cylinder barrel 5 is covered with a rubber protective cover 7, and the rubber protective cover is an elastic member, which is directly placed on the outer side of the cylinder barrel 5 and connected by elastic means. The cylinder head 2 is an annular groove structure, and the annular groove of the U-shaped thin-walled cylinder head 2 is provided with a cylinder head stop sleeve 34, and the piston head buffer assembly 35 is installed in the cylinder head stop sleeve 34, and the piston rod 9 The other end passes through the center hole of the cylinder head stopper 34 and the piston head buffer assembly 35 in sequence, and is fixedly connected with the piston head buffer assembly 35 by threads; the piston head 27 is provided with a damping hole e28 and a damping hole d13 , the rod chamber 29 communicates with the rodless chamber 25 through the damping hole e28 and the damping hole d13; the damping hole e28 and the damping hole d13 are inclined or L-shaped or Z-shaped, or other structures that can achieve equivalent functions. Both sides of the piston head 27 are respectively equipped with a valve plate a12 and a valve plate b14; the valve plate a12 and the valve plate b14 are respectively sleeved on the piston rod 9 and fixedly connected by bolts; the damping hole e28 provided on the piston head 27 is The valve plate a12 is covered, and the damping hole d13 is covered by the valve plate b14; the variable damping control valve 16 and the outer cylinder 11 close to the lower end cover 18 of the inner cylinder are fixedly connected by bolts, and the damping hole c15 on it is connected to the oil storage chamber of the outer cylinder 26, the damping hole b17 communicates with the rodless chamber 25; the inner cylinder 8 is provided with a damping hole f30 near the rod chamber 29, and the rod chamber 29 communicates with the outer cylinder oil storage chamber 26 through the damping hole f30, which can make the rod The cavity 29 circulates with the oil in the oil storage cavity 26 of the outer cylinder.

The air compressor 36 and the air compressor control unit 37 are integrally installed on the vehicle suspension and electrically connected to the signal control center 42. The front axle height sensor 38 is installed on the front axle of the vehicle frame, and the rear axle height sensor 39 is installed on the vehicle suspension. frame the rear axle to accurately measure the height of the vehicle frame, and be electrically connected with the signal control center 42, and transmit the height signal to the signal control center 42; the signal input end of the pressure sensor 41 is electrically connected with the air compressor control unit 37, and the signal The output end is electrically connected with the signal control center 42, and is used to measure the pressure of the air bag 4, and the pressure signal is transmitted to the signal control center 42; the signal control center 42 is electrically connected with the variable damping control valve 16; the signal processing center 42 is connected to the air pressure The machine control unit 37 and the variable damping control valve 16 issue instructions, the air compressor control unit 37 controls the air compressor 36 to work, and the variable damping control valve 16 is adjusted to the corresponding compression damping coefficient at the same time; the instrument display 40 and the signal control center 42 electrical connections for real-time display of detection data of each electrical part.

The working principle of the present invention is as follows:

As shown in Figures 2 and 3, when the shock absorber is compressed, the pressure of the oil in the rodless chamber 25 increases, and the high-pressure oil is divided into three ways to be discharged: one way passes through the damping hole e28 on the piston head 27 to open the valve plate 12 Enter the rod chamber 29; the other way enters the compensation chamber 23 through the damping hole a24 on the lower end cover 18 of the inner cylinder, and squeezes the floating piston 19 to move down, compressing the air spring 22; the last way enters the variable damping control valve through the damping hole b17 16. The oil from the variable damping control valve 16 enters the oil storage chamber 26 of the outer cylinder through the damping hole c15, and finally enters the rod chamber through the damping hole f30 on the inner cylinder 8; since the front wheel is compressed first, the front axle The height sensor 38 and the rear axle height sensor 39 sense "nodding", and transmit the corresponding height signal to the signal processing center 42, and the signal processing center 42 sends instructions to the air compressor control unit 37 and the variable damping control valve 16, and the air The compressor control unit 37 controls the air compressor 36 to inflate the air bag 4 to raise the front of the car, and at the same time, the variable damping control valve 16 is adjusted to the corresponding compression damping coefficient;

As shown in Figures 2 and 4, when the shock absorber is stretched, the oil in the rod chamber 29 flows to the rodless chamber 25 through two paths. One way passes through the damping hole d13 on the piston head 27 to open the valve plate 14 and flows into the rodless chamber 25, the other way passes through the damping hole f30 on the inner cylinder 8 and enters the oil storage chamber 26 of the outer cylinder, and then enters the variable damping control through the damping hole c15 The valve 16 finally flows into the rodless chamber 25 through the damping hole b17; at the same time, under the pressure of the air spring 22, the floating piston 19 moves upward, and the oil in the compensation chamber 23 passes through the damping hole a24 on the lower end cover 18 of the inner cylinder and is released. Press into the rodless chamber 25. At this time, the front axle height sensor 38 and the rear axle height sensor 39 sense the "head up", and transmit the corresponding height signal to the signal processing center 42, and the signal processing center 42 sends the air compressor control unit 37 and the variable damping control valve 16 issues an instruction, and the air compressor control unit 37 communicates with the pipeline of the air bag 4 to be exhausted to lower the front of the vehicle, while the variable damping control valve 16 is adjusted to the corresponding stretching damping coefficient.

Cylinder head 2, air bag 4 and cylinder barrel 5, inner barrel 8 and outer barrel 11 are connected to form a closed air pressure chamber, and are connected to the air pressure regulating system through air valves and related pipelines; inner barrel 8 is closed by piston head 27 Divided into a rod chamber 29 and a rodless chamber 25; the outer cylinder 11 is fixedly sleeved on the inner cylinder 8, and is isolated by the lower end cover 18 of the inner cylinder into an outer cylinder oil storage chamber 26 and a floating piston oil storage chamber 23; variable damping control The valve 16 is fixedly connected with the outer cylinder 11 through a transition plate, and its two oil ports communicate with the oil storage chamber 26 and the rodless chamber 25 of the outer cylinder respectively; the floating piston 19 is installed in the outer cylinder 11 to isolate the oil from the air spring chamber, and A detachable outer cylinder plug 20 with an inflation valve 21 is provided. The oil circulates back and forth in the rodless cavity 25 and the rod cavity 29 through the variable damping control valve 15 and a series of damping holes, and cooperates with the height adjustment system to make the corresponding height when the shock absorber is compressed or stretched. Compensation, good vibration reduction effect and ride comfort can be obtained.

It should be understood that although this description is described according to various embodiments, not each embodiment only includes an independent technical solution, and this description of the description is only for clarity, and those skilled in the art should take the description as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiment or All changes should be included within the protection scope of the present invention.

Claims (10)

1. A variable damping automotive hydraulic shock absorber with a height adjustment system is characterized in that it comprises a damping system and a height adjustment system; the damping system includes a piston rod (9), a piston head (27), a spring Assembly (10), inner cylinder (8), outer cylinder (11) and variable damping control valve (16); the height adjustment system includes air compressor (36), air compressor control unit (37), front axle Height sensor (38), rear axle height sensor (39), pressure sensor (41), signal control center (42), cylinder head (2), air bag (4) and cylinder barrel (5); One end of the piston rod (9) is threadedly connected with the piston head (27) and coaxially installed in the inner cylinder (8), and the piston head (27) is interference fit with the inner cylinder (8); The cylinder (8) is a cylinder-type thin-walled structure, one end is blocked by the lower end cover (18) of the inner cylinder, and the other end is blocked by the upper end cover (6) of the inner cylinder; the other end of the piston rod (9) passes through the upper end of the inner cylinder The central hole of the cover (6) protrudes, and the piston rod (9) is placed on the inner section of the inner cylinder (8) through the piston guide and sealing assembly (31) to achieve a sealed connection; the spring assembly (10) is located in the inner One end of the spring assembly (10) abuts on the piston head (27), and the other end abuts on the piston guide and sealing assembly (31); The outer cylinder (11) is sleeved on the outside of the inner cylinder (8) and sealed with the lower end cover (18) of the inner cylinder; because the diameter of the lower end cover (18) of the inner cylinder is larger than that of the inner cylinder (8), the outer cylinder (11 ) and the inner cylinder (8) form an annular outer cylinder oil storage chamber (26); The cylinder barrel (5) is a U-shaped thin-walled structure, the lower end is sleeved on the outer cylinder (11), the upper end is fixedly connected with the inner side of the airbag (4), and the outer side of the airbag (4) is fixedly connected with the lower end of the cylinder head (2) , the cylinder head (2) is provided with an air valve joint (1); The cylinder head (2) has an annular groove structure, and a cylinder head stopper (34) is arranged in the annular groove, and the piston head buffer assembly (35) is installed in the cylinder head stopper (34), and the piston rod (9) One end extending outside the inner cylinder (8) passes through the center hole of the cylinder head stop sleeve (34) and the piston head buffer assembly (35) and is threadedly connected with the piston head buffer assembly (35); The piston head (27) is provided with a damping hole e (28) and a damping hole d (13), and the rod chamber (29) and the rodless chamber (25) pass through the damping hole e (28) and the damping hole d (13) connected; The variable damping control valve (16) is connected with the outer cylinder (11) by bolts near the lower end cover (18) of the inner cylinder, and the damping hole c (15) on it communicates with the oil storage cavity (26) of the outer cylinder, The damping hole b(17) communicates with the rodless chamber (25); the inner cylinder (8) is provided with a damping hole f(30) on the side close to the rod chamber (29), and the rod chamber (29) is connected to the oil storage chamber of the outer cylinder (26) communicate through the damping hole f (30); The air compressor (36) and the air compressor control unit (37) are integrated and installed on the automobile suspension, the front axle height sensor (38) is installed on the front axle of the vehicle frame, and the rear axle height sensor (39) is installed on the vehicle frame The rear axle is used to measure the height of the vehicle frame and transmit the height signal to the signal control center (42); the signal input end of the pressure sensor (41) is connected with the air compressor control unit (37), and the signal output end is connected with the signal control center (42); The center (42) is connected to measure the pressure of the air bag (4) and transmit the pressure signal to the signal control center (42); the signal processing center (42) sends air compressor control unit (37) and variable damping control valve (16) An instruction is issued, and the air compressor control unit (37) controls the work of the air compressor (36), while the variable damping control valve (16) is adjusted to the required compression damping coefficient. 2. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, characterized in that it also includes a floating piston (19); the end of the outer cylinder (11) is provided with an outer cylinder plug head (20); the floating piston (19) is installed in the outer cylinder (11) between the lower end cover (18) of the inner cylinder and the plug (20) of the outer cylinder, and has an interference fit with the outer cylinder (11); A compensation cavity (23) is formed between the lower end cover (18) of the inner cylinder and the floating piston (19), and a plurality of damping holes a (24) communicating with the compensation cavity (23) are provided on the lower end cover (18) of the inner cylinder ; An air spring (22) is placed between the floating piston (19) and the plug (20) of the outer cylinder. 3. The variable damping automobile hydraulic shock absorber with a height adjustment system according to claim 2, characterized in that, the outer cylinder plug (20) is connected to the outer cylinder (11) through threads. 4. The variable damping automotive hydraulic shock absorber with height adjustment system according to claim 2, characterized in that, said outer tube plug (20) is provided with an inflation valve (21); said inflation valve ( 21) Tighten on the outer cylinder plug (20) by thread. 5. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, characterized in that valve plate a (12) and valve plate b ( 14); the valve plate a (12) and the valve plate b (14) are respectively sleeved on the piston rod (9) and fixedly connected by bolts; The damping hole e (28) is covered by the valve plate a (12), and the damping hole d (13) is covered by the valve plate b (14). 6. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, characterized in that, it also includes an airbag protective cover (3); the upper end of the airbag protective cover (3) is connected to the The cylinder head (2) is connected. 7. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, characterized in that, the outer side of the cylinder barrel (5) is covered with a rubber protective sleeve (7). 8. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, further comprising a rubber buffer sleeve (32); the rubber buffer sleeve (32) is sleeved on the piston rod (9 ), and located on the outside of the inner cylinder (8), the outside of the rubber buffer sleeve (32) is surrounded by a U-shaped outer cover guide sleeve (33), and the small end of the U-shaped outer cover guide sleeve (33) is sleeved on the piston rod (9) and push against the lower end of the piston head buffer assembly (35). 9. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, further comprising an instrument display (40); the instrument display (40) is connected to the signal control center (42) Connected, and the detection data of each electrical part can be displayed in real time. 10. The variable damping automotive hydraulic shock absorber with a height adjustment system according to claim 1, characterized in that, the damping hole e (28) and the damping hole d (13) are inclined or L-shaped or Z-shaped shape.